1. Field of the Invention
The present invention relates to a technology for relaying a communication between a transmitting side and a receiving side.
2. Description of the Related Art
Recently, an Internet protocol (IP) network is broadly in use, in which data transmitted from a transmitting side is relayed to a receiving side by a plurality of relay devices (such as a router and a switch). In such communication network, network reachability between the transmitting side and the receiving side is often checked using a program called packet Internet groper (ping) or the like. Specifically, the transmitting side transmits predetermined small-sized data to the receiving side, so that the transmitting side can check the network reachability based on a response from the receiving side to the transmitted data.
To manage the relay devices in an efficient manner, a technology is disclosed in Japanese Patent Application Laid-Open No. 2004-23120. In the above technology, if a transmitting device issues an instruction for starting a check in a network called a virtual local area network (VLAN), a single relay device (a route node) transmits a test packet to collect VLAN set data as a response packet from other relay devices in the same network. As a result, it is possible to improve an efficiency of a management of the relay devices.
For a maintenance and a management of such network, a technology is further developed, in which a monitoring server provided for each network collects state data defined as management information base (MIB) of a device. With this technology, it is possible to efficiently manage a network configuration and an operation state of the relay device provided between the transmitting device and the receiving device, as well as to check the network reachability.
However, with the above technologies, a cause of a degradation of the throughput can be hardly identified when a desired throughput cannot be obtained even with the network between the transmitting device and the receiving device in a reachable state. In other words, if a communication bandwidth for a relay device is narrowed due to an erroneous setting in the relay device, the communication bandwidths between the relay device and other relay devices become inconsistent, so that an expected throughput cannot be obtained in the receiving device. In this case, an error cannot be detected, because a user can confirm that the network is in a reachable state, and network configuration data or the like can be transmitted and received between the transmitting device and the receiving device. Therefore, it is problematic that a desired throughput appropriate for a subscription fee may not be provided to the user in a communication service that charges the user depending on a bandwidth.
Furthermore, even when it is detected that the desired throughput is not being provided in the receiving device, a cause of a degradation of the throughput can be hardly identified because there are a number of relay devices involved. In other words, it is difficult to identify a relay device or a network line having an erroneous setting or a failure.
If the state data of each of the relay devices is collected using the MIB described above, it is possible to identify a cause of the degradation of the throughput. However, because the MIB is not sufficiently standardized, it is necessary to provide a monitoring server compliant to each of the relay devices if the relay devices are provided by different service providers. Accordingly, it is difficult to control and manage all the relay devices provided in the network when the transmitting device and the receiving device belong to different networks, respectively.